A New York-based artist was questioned by the New York City Police Department and the Secret Service yesterday over an exhibition that may have been at least partly a hoax.

A spokesman for the police, Paul Browne, said that a woman called 911 yesterday morning reporting threatening signs in a storefront in midtown. The signs on the storefront, at 264 West 40th Street, said “The Assassination of Hillary Clinton & The Assassination of Barack Obama.” The police alerted the Secret Service, who briefly detained the artist responsible for the sign, Yazmany Arboleda, and then released him without charges.

But what was the exhibition in question? Elaborate Web sites show pictures of images dissecting what Mr. Arboleda calls the “character assassination” of the candidates. In an interview, Mr. Arboleda claimed that the exhibitions were installed separately in March in two Chelsea art galleries, the Leah Keller Gallery and the Naomi Gates Gallery, but they were shut down after a week.

Phone calls to the galleries (whose Web sites were only reachable through Mr. Arboleda’s own) were not returned.

Mediabistro.com reported yesterday afternoon that Mr. Arboleda had himself sent out elaborate press releases about the exhibitions supposedly being shut down. On April 5, the Miami Herald ran a story in which he claimed that the shows closed after the galleries “came under pressure from the campaigns and other political heavyweights.”

On one of Mr. Arboleda’s many Web sites, www.theassassinationofart.com, an invitation to the midtown installation includes the logos of both the Lower Manhattan Cultural Council and Altria. Asked if he had received funding from either LMCC or Altria, Mr. Arboleda said he had not. “That installation is part of the art,” he said.

Mr. Arboleda was supposedly renting the midtown space under the auspices of an organization called “An Available Space,” but it is not clear whether that organization exists.

Asked to provide a number of someone affiliated with An Available Space, Mr. Arboleda offered a number for someone he referred to as Charles Taylor. The person who answered the phone laughed off suggestions that “An Available Space” was simply a front for Mr. Arboleda’s work, but was unable to provide evidence that it existed separately. Asked where the organization got funding, he said: “Public funding… New York City Cultural Arts, or whatever that organization is that gives funding to cultural non-profits.”

A spokeswoman for the New York City Department of Cultural Affairs said that “An Available Space” was not a grantee.

Mr. Browne said last night that the police still believe the 911 call to have been legitimate.